In the clearest public signal yet that the government wants a hi-tech farming revolution, Professor John Beddington will say UK scientists need to urgently develop “a new and greener revolution” to increase food production in a world changed by global warming and expected to have an extra 3 billion people to feed by 2040.

“Techniques and technologies from many disciplines, ranging from biotechnology and engineering to newer fields such as nanotechnology, will be needed,” writes Beddington in a paper, seen by the Guardian, to accompany his speech to the Oxford farming conference.

He warns that time lags for the use of new technology on farms means action is vital now and argues that it is no longer possible to rely on improving yields from crops in traditional ways. “Over the last 50 years improving yields has accounted for 75% of increase in output. However, yield growth rates are now slowing,” he says.

Instead, he argues that new technologies such as GMwill be critical in meeting economic, environmental and social goals. Beddington says the revolution is needed primarily to counter climate change and help provide food for the 9 billion people worldwide expected within 30 years.

“It is [also] predicted that demand for energy will rise by around 50%, and for fresh water by 50%, all of which must be managed while mitigating and adapting to climate change. This threatens to create a ‘perfect storm’ of global events,” he says.

The government has wanted GM crops to be much more freely grown for many years but has been reluctant to reopen the debate following intense campaigns against the technology by environment and development groups in the 1990s.

Although Beddington has spoken in support of GM before, his keynote speech – to a conference of farmers and supermarkets – shows that ministers believe it is time to accelerate the debate on the issue.

, the growing significance of climate change, recent international food crises and a major independent Royal Society report have all helped to give the government the authority to put GM back on the national agenda.

For six months the government has been preparing the way with a series of reports on consumer opinion. Announcements from the Department for the Environment, Food and Rural Affairs (Defra) over the summer also began to frame GM as a new moral imperative in feeding the world. The Cabinet Office strategy unit also highlighted GM as an urgent domestic issue back in the summer of 2008. It said: “Consumer confidence in UK regulations, regulators and food supplies might be prejudiced if GM feed was found in systems claiming to be GM-free or if non-authorised varieties were detected in the UK food chain. If non-authorised material is found, there are also significant cost implications associated with recall.”

The assumption that new technology is the answer to the global food crisis is expected to be fiercely challenged by development and environmental charities campaigners who accuse the government of not having looked at the real causes of the global food crisis.

They point out that an UN-sponsored four-year review, involving more than 400 international scientists and chaired by Defra’s own chief scientist, Professor Robert Watson, concluded in 2007 that GM technologies were unlikely to have more than a limited role in tackling global hunger.

According to the Watson-led review, the scientific evidence on the claimed benefits of GM suggests they are variable, with increases in yield in some areas but decreases in others, and both greater and lesser pesticide use in different contexts. But crucially it concluded that global hunger is as much to do with power and control of the food system as with growing enough food.

Yesterday, Hilary Benn, the environment secretary, launched the government’s food strategy for the next 20 years. He told the Oxford conference that Britain must grow more food in a different way to respond to rising temperatures and world populations. “Food security is as important to this country’s future wellbeing – and the world’s – as energy security. We need to produce more food.

“We need to do it sustainably. And we need to make sure that what we eat safeguards our health,” he said.